Valvular Heart Disease: The Aortic Valve

Case A 60 year old Asian female with a history of a heart murmur presents for a routine visit. She has no complaints. Vitals are normal. A 4/6 mid systolic murmur is noted at the left upper sternal border. An EKG shows no abnormalities.

Case What is the next best step? – Do nothing, this murmur is benign – Do an exercise stress test to try to elicit symptoms of aortic stenosis. – Do nothing, the patient has had this murmur for a long time – Check an echocardiogram – Refer the patient to a cardiologist for further evaluation

Case I: Echocardiogram

Case What is the next best step – Do nothing because aortic stenosis is not severe – Start a beta blocker and ACE-I for optimal blood pressure control – Refer the patient to a cardiac surgeon for repair – Refer the patient to a cardiologist for further evaluation

What Makes A Heart Murmur? High blood flow through a normal or abnormal orifice Forward flow through a narrowed or irregular orifice Backward flow through an incompetent valve

These Murmurs Are Benign Mid systolic murmur at the left sternal border with grade 2 or less with a normal S1 and S2 and no other abnormal findings in an otherwise asymptomatic patient Associated with normal or increased blood flow across normal valves

These Murmurs Need Further Evaluation Diastolic Murmurs Continuous Murmurs Systolic – Loud – Early systolic – Late systolic – Holosystolic

Strategy For The Evaluation Of Cardiac Murmurs Bonow. JACC

When To Order An Echo Class I – Diastolic, continuous, holosystolic, late systolic, clicks, radiation to neck or back – Symptoms of underlying cardio-pulmonary disease – Grade 3 or louder mid systolic murmurs Class III – Mid systolic mumur grade II or less thought to be innocent

Aortic Valve Stenosis Obstruction of LV outflow Common causes – Bicuspid – Degenerative calcific – Rheumatic Rare causes – Congenital – Severe aortic atherosclerosis – Rheumatoid – Alkaptonuria Flather. Lancet, 2000.

Aortic Valve Characteristics Normal Aortic Valve – Valve area 3-4 cm2 Valve stenosis – 25% of normal valve area Hemodynamic Progression – 0.12 cm2/year – 0.32 m/s increase in jet velocity/year – 7 mmHg increase in mean gradient/year

Epidemiology Most common disease in western world – 50,000 valve replacements annualy – Age 65: 2% of patients – Age >80: >4% – 1 billion dollars annually in US

Etiologies of Aortic Stenosis Baumgartner. JASE, 2009.

Etiologies of Aortic Valve Disease Libby. Braunwald’s Heart Disease. 8 th Ed.

Bicuspid Valve 1-2% of births Generalized arteriopathy: fragmentation of fibers of the elastic media – Coarctation, aortic dilation, dissection (5-9x risk) Most common reason for valve replacement <70 years old Roughly 66% of replaced valves < 70 More common in men: 70-80% of cases Hemodynamic abnormalities predispose to earlier stenosis Roberts. Circulation, 2005.

Bicuspid Aortic Valve

Calcific AS Most common cause of AS Present in 2% of adults 65 or older Becomes symptomatic age Sclerosis present in 29% ≥ 65 Proliferative and inflammatory changes-> calcification and bone formation Risk Factors: HL, tob, HTN, DM

Rheumatic AS Adhesions and fusion of commisures and cusps Vascularization of leaflets-> retraction and stiffening of the free borders of the cusps Calcific nodules Small triangular orifice Coexists with rheumatic mitral valve disease

Time Between Rheumatic Fever and Symptoms of Stenosis

Development of AS Otto. NEJM

Pathophysiology of AS Progressive obstruction and compensatory change Pressure overload->increased wall stress- >increased wall thickness Increased myocardial collagen Progressive systolic dysfunction Progressive diastolic dysfunction Decreased coronary blood flow

Pathophysiology Libby. Braunwald’s Heart Disease. 8 th Ed.

Law of Laplace Yousef. BMJ

Pathologic LV Hypertrophy Sorajja. Contemporary Cardiology, 2009.

Clinical Course Outcome similar to normal in asymptomatic patients Progression from sclerosis to severe AS: 2.5% in 8 years Mortality is high in patients with symptomatic disease Cosmi. Arch Int Med

Progression of Asymptomatic AS Otto. Circulation

Mortality In Symptomatic Aortic Stenosis Is High Levy. NEJM, Ross J Jr, Braunwald E: Aortic stenosis. Circulation 38:V61, 1968

Survival With Or Without Valve Replacement Carabello. NEJM, Schwarz. Circulation, 1982.

Clinical Presentation Age – Bicuspid: years old – Calcific: > 70 years old Symptoms – Progressive exercise intolerance – Angina (2/3 with significant CAD) – Syncope – Endocarditis, systemic embolization

Physical Examination Carotid upstroke – Parvus and tardus: slow rising, late peaking – Specific but insensitive Systolic murmur – Late peaking heard at the base Varies beat to beat Louder with increased flow: squatting Quieter with decreased flow: standing – Stops before A2 – Can radiate to the apex (Gallivardin phenomenon) Second heart sound – Absent A2 with severe disease Signs of heart failure Libby. Braunwald’s Cardiology. 8 th Ed.

Aortic Stenosis Carotid Pulse Waveforms Libby. Braunwald’s Heart Disease. 8 th Ed.

Dynamic Auscultation Intervention Hypertrophic Obstructive CardiomyopathyAortic Stenosis Mitral Regurgitation Mitral Valve Prolapse Valsalva↑↓↓↑ or ↓ Standing↑↑ or unchanged ↓↑ Handgrip or squatting ↓↓ or unchanged ↑↓ Supine position with legs elevated ↓↑ or unchanged Unchanged↓ Exercise↑↑ or unchanged ↓↑ Amyl nitrite↑↑↑↓↑ Isoproterenol↑↑↑↓↑ Libby. Braunwald’s Heart Disease. 8 th Ed.

EKG and CXR EKG – LVH – Atrial enlargement – Conduction abnormalities Chest XR – Rounding of LV border and apex

Further Assessment Unclear symptoms – Treadmill exercise testing Development of symptoms Failure to increase BP > 10 mmHg NOT IN SYMPTOMATIC PATIENTS Low left ventricular function – Dobutamine infusion

Low Cardiac Output: Response to Dobutamine Infusion Sorajja. Contemporary Cardiology, Increase in CO and grad. No change in AVA. Increase in CO. No change in grad. No change in CO, dec grad and hypotension.

Echocardiogram in AS Valve anatomy definition LV hpertrophy and systolic function Transaortic velocities and gradients

Echo Assessment of Aortic Stenosis Baumgartner. JASE, 2009.

Severity of Aortic Stenosis MildModerateSevere Jet Velocity (m/s) >4.0 Mean gradient (mmHg) < >40 AVA (cm2)> <1.0 Baumgartner. JASE, 2009.

Medical Therapy For Aortic Stenosis

Bonow. JACC, 2006.

Non-Operative Management of Aortic Stenosis Counseling to monitor for symptoms Evaluate and treat CAD Reassessment – For symptoms changes – Severe: Annually – Moderate: 1-2 years – Mild 3-5 years Balloon valvulotomy

When To Refer To Cardiology All symptomatic AS with LV dysfunction Asymptomatic progressive disease Atypical presentations

Operative Management Of AS Class I – Symptomatic – Severe AS undergoing cardiac surgery – Severe AS and EF < 50% Class II – Moderate AS undergoing cardiac surgery – Asymptomatic with severe AS and abnormal ex response – Asymptomatic severe with risk of rapid progression – Mild AS undergoing cardiac sx, concern for rapid progression – Very severe asymptomatic with low op mortality

Surgical Mortality 3-4% for AVR alone % with AVR plus CABG 33% increased mortality in low volume centers

Surgical Risk Calculator euroscore.org/

Transcatheter Aortic Valve Replacement May Be An Option For High Risk Patients

Transcatheter Aortic Valve Replacement For High Risk Patients Leon. NEJM, 2010.

Aortic Regurgitation Leaflets (46%) – Degenerative (75% with some AR) – Endocarditis – Trauma – Congenital – Rhematic – Myxomatous – Systemic disorders: SLE, giant cell and Takayasu’s, ankylosing spondylitis, Whipple’s, Chron’s, weight loss drugs Aorta (54%) – Age – Degenerative disease (Marfan) – Dissection – HTN – Syphilis – Ankylosing spondylitis – Giant cell arteritis – Behcet syndrome – Psoriatic arthritis – Osteogenesis imperfecta – Reieter syndrome – Relapsing poychondritis Rigolin. Contemporary Cardiology, Roberts. Circulation, 2006.

Pathophysiology LF ejection split between forward and back Total stroke volume is increased Left ventricle dilates to accommodate stroke volume Increased LVEDP and hypertension -> increased preload and afterload -> eccentric hypertrophy Mismatch-> systolic dysfunction -> fibrosis-> dysfunction becomes permanent

Pathophysiology Libby. Braunwald’s Cardiology. 8 th Ed.

Clinical Presentation Long asymptomatic period LV dysfunction -> EDV and EDP increase Increase right sided pressures Cardiac output falls Exercise tolerance develops

Physical Exam Findings secondary to increased stroke volume and widened pulse pressure Apical impulse: diffuse, laterally-inferiorly displaced, hyperdynamic Carotid pulse: Corrigan’s, bifid S1 normal, S2 variable LSB blowing diastolic murmur, Austin Flint murmur Libby. Braunwald’s Heart Disease. 8 th Ed.

Peripheral Signs of AI Rigolin. Contemporary Cardiology, 2009.

LVH and Strain In Aortic Regurgitation Rigolin. Contemporary Cardiology, 2009.

Cardiomegaly In Aortic Regurgitation Rigolin. Contemporary Cardiology, 2009.

Echo Assessment Of AI LA size Leaflet appearance Jet width, density, deceleration, diastolic flow reversal VC width, calculated regurgitant volume and EROA Zoghbi. JASE, 2003.

Echo Assessment Of AI Zoghbi. JASE, 2003.

Aortic Regurgitation Clinical Course Bonow. JACC, 2006.

Medical Therapy Class I recommendation – Severe AR with symptoms or LV dysfunction and unable to undergo surgery Class IIa – Bridge to surgery in patients with severe LV dysfunction Class IIb – Long term in severe AR with LV dilation but normal function Hydralazine, nifedipine have been studied

No Benefit To Vasodilators In Asymptomatic AR Evangelista. NEJM, 2005.

Survival After AI Repair By Pre-Op EF Rigolin. Contemporary Cardiology, 2009.

Bonow. JACC, 2006.